What is the rate of simple interest? I. The total interest earned was Rs. 4000. II. The sum was invested for 4 years.

1. A Option A: I alone sufficient while II alone not sufficient to answer
2. B Option B: II alone sufficient while I alone not sufficient to answer
3. C Option C: Either I or II alone sufficient to answer
4. D Option D: Both I and II are not sufficient to answer
5. E Option E: Both I and II are necessary to answer

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